Answer:
Option D is correct.
Explicit formula for the geometric sequence is, 
Step-by-step explanation:
Geometric sequence states that a sequence of numbers in which the ratio between consecutive terms is constant,
we can write a formula for the nth geometric sequence in the form of:
.....[1] where
is the first term and r is the common ratio between successive term.
Given the sequence: 64, 32, 16 , 8......
Here, first term (
) = 64.
Common ratio(r) = 0.5
Since,

,
......
Substitute the value of a and r in [1] we get;

therefore, the explicit formula for the geometric sequence is, 
1186.30/999=1.187
1.187*1.187=1.409
One of the main reasons you have to show work for math is because your teacher needs to know that you understand the concept. Also, showing work helps your teacher know that you didn't cheat using an online calculator that just gives you an answer.